1. Field of the Invention
The present invention relates to an object lens actuator and a disc drive using the actuator.
2. Related Art of the Invention
In a disc drive for writing information onto disc-shaped information writing media or playing written information, a higher data transfer rate is facilitated by rotating an optical disc at a high speed.
For this reason, the disc drive may need to write or play information correctly by making a position of a focal point of an object lens follow a track on a disc. The disc drive includes an object lens actuator to move the object lens in the focusing direction and the tracking direction.
Popular object lens actuators include a magnetic circuit having a yoke and a permanent magnet, a moving part having a lens holder attaching an object lens, a focusing coil, and a tracking coil thereto, and a securing part elastically supporting the moving part movably via linear support members.
In such an object lens actuator, when the object lens is tilted, aberration may occur to worsen quality of writing and play signals. Therefore, it may be necessary to inhibit the tilt of the object lens.
As a related art of inhibiting a tilt of an object lens, an object lens actuator disclosed in JP-A No. H08-297847 (Claim 9, FIGS. 10 to 13) is known in which a plate spring is attached to a raised portion of a securing base (hereinafter called a yoke) by use of securing screws and a projection is provided downward from a bottom surface of the yoke. In JP-A No. H08-297847 (Claim 9, FIGS. 10 to 13), two screws are used for assembling to adjust a tilt of the object lens by use of the projection as a fulcrum while biasing the yoke by use of the plate spring.